As shown in FIG. 1, a conventional pre-press imaging system 100 commonly includes a raster image processor (RIP) 105, or other type image processor, a print drive server (PDS) 110, and one or more image maker (IM), such as a pre-press image setter (PPIS) 115 having an optical scan assembly, e.g. a laser scanner, and a support surface, e.g. a cylindrical drum and/or an image proofer (IP) 120, e.g. a color proofing device.
In operation, the RIP 105 receives, as input, a digitized image from a front-end processor (not shown) or via a user commands entered on a user input device (not shown), and processes the received input to generate raster image data representing the input image. The raster image data is transmitted from the RIP 105 to the PDS 110, and subsequently processed by the PDS 110 to generate appropriate instructions for the applicable IM 115 or 120. These instructions are transmitted from the PDS 110 to the IM 115 or 120.
For example, if an IP 120 is included as part of the system, the instructions for the IP 120 may be transmitted by the PDS 110 to the IP 120 prior to instructions being transmitted by the PDS 110 to the PPIS 115. The IP 120 operates in accordance with the received PDS instructions to generate an image proof, e.g. a color proof, for inspection by a system operator, as is well understood in the art. If the proof is deemed acceptable, PDS instructions for the PPIS 115 are transmitted to the PPIS 115. In accordance with these received instructions, the optical scan assembly of the PPIS 115 operates to scan the image represented by the PDS instructions onto a plate or film supported by the support surface of the PPIS 115. In this way, the input image is transferred to the plate or film, which in turn can be used to print the input image on other media, e.g. paper.
More recently, enhancements in print drive server capabilities, and particularly the introduction of the AGFA™ Apogee™ print drive server, have allowed multiple RIP to be serviced by one or more PDS. FIG. 2, depicts a convention networked imaging system 200 with an Ethernet network 225 linking multiple RIPs 205 to a single PDS 210. It will be recognized that additional PDS could also be linked to the multiple RIPs 205 via the network 225 if so desired. The RIPs 205 and PDS 210 are typically configured on separate workstations, and communicate via the network 225. However, if desired, a single workstation could serve as both the PDS 210 and one of the RIPs 205.
In operation, each of the networked system RIPs 205 processes received input to generate raster image data. The applicable RIP 205 then typically transmits this data via the network 225 to a remote storage device 230, i.e. typically a storage device remote to both the applicable RIP 205 and the PDS 210, but accessible to both the applicable RIP 205 and PDS 210 via the network 225. The transmitted raster image data is written into a storage file of the remote storage device 230. The remote storage device 230 could, for example, be a magnetic or optical disk or some other type storage device.
The stored data is retrieved, typically via the network 225, by the PDS 210 from the remote storage device 230 by reading the applicable storage file when needed. The read raster image data is transmitted to the PDS 210 via the network 225, and processed to generate instructions for the applicable IM 215 and/or 220. These instructions are in turn transmitted to the applicable IM 215 and/or 220, either via a dedicated link 227 in the case of the PPIS 215, or via the network 225 in the case of the IP 220.
However, in the case where the RIP 205 and PDS 210 are implemented in a single workstation, the raster image data generated by that RIP 205 will typically be stored in a local storage device (not shown). In such a case, there is no need to transmit the raster image data via the network 225. Furthermore, even in the case where the RIP 205 and PDS 210 are implemented on separate workstations, the raster image data generated by that RIP 205 may be stored in a storage device local to the applicable RIP 205 or the PDS 210. In the case where the storage device is local to the RIP 205, there will be no need for the RIP 205 to transmit the raster image data via the network 225 to the storage device 230. In the case where the storage device is local to the PDS 210, there will be no need for the PDS 210 to retrieve the stored raster image data via the network 225 from the storage device 230. Hence, in either of these later cases only a single transmission of the raster image data over the network 225 is required.
When a job begins, the RIP 205 requests a destination storage device and path from the PDS 210. If the RIP 205 and PDS 210 are implemented on same workstation, the destination storage device will normally be a local storage device and the raster image data is simply written as a file to local storage. If not, the destination drive and path request is communicated via a network 225.
If the PDS 210 destination storage device letter designation e.g. “drive C” provided to the RIP 205 in response to the request is to a remote, mapped storage device 230, the RIP 205 will transmit the raster image data over the network 225 and the data will be written directly to storage at the designated storage device 230 via remote file access by the RIP 205.
On the other hand, if the PDS 210 destination storage device letter designation is to a remote, at least with respect to the RIP 205, unmapped device, e.g. a storage device local to the PDS 210, the RIP 205 will transmit the raster image data over the network 225 to the PDS 210. The PDS 210 will then transmit the raster image data over the network 225 and the data will be written to storage at the designated storage device via remote file access by the PDS 210.
If the PDS 210 destination storage device letter designation is not to a remote storage device, but rather to a storage device which is local to the RIP 205, the raster image data is simply written as a file to local storage.
In all of the above cases, the RIP 205 informs the PDS 210 that the image data has been written once storage has been completed.
Pseudo code for the above is as follows:                1) RIP→PDS: Query, where should data be written?*        2) PDS→RIP: Response, X:\path\ . . . \filename*        3) RIP Processing                    a) if RIP and PDS are on different workstations (i) and if X is a remote, mapped drive write image data via remote file system*,(ii) and else write image data via PDS interface*            b) else write image data to local drive                        4) RIP→PDS: Data has been written*                    where *=Ethernet transmission                        
The electronic pre-press workflow involves the generation of large amounts of raster image data by the RIPs 205 and the consumption of this data by an IMs, e.g. the PPIS 215 and the IP 220. As discussed above, often the RIP 205 stores the raster image data at and the PDS 210 retrieves the stored raster image data from a remote storage device 230. In such cases multiple transmissions of the raster image data via the network 225 are required, i.e. transmissions to and from the applicable storage device 230.
Furthermore, on occasion the RIP 205 may store the raster image data at and the PDS 210 may retrieve the stored raster image data from a storage device which is local to either the applicable RIP 205 or the PDS 210, but not to both. In such cases, at least one transmission of the raster image data via the network 225 is still required, i.e. transmissions to or from the applicable storage device.
Although conventional networked imaging systems developed since the introduction of AGFA™ Apogee™ print drive server are a vast improvement over imaging systems developed prior to the introduction of the AGFA™ Apogee™ print drive server, conventional networked imaging systems, such as that depicted in FIG. 2, have experienced certain problems which has been difficult to overcome.
More particularly, because of the large amounts of raster image data which must be communicated via these networks, the transmission(s) of this data over the network 225 can significantly degrade the overall performance of the network 225. The uncompressed image data for a normal four color job can exceed 10 Gigabytes. Data compression and decompression help to reduce the amount of data which must be transmitted and stored, but even in compressed form the raster image data can be quite large, e.g. more than 1 Gigabyte per job.
If a large amount of network bandwidth is allocated to each such transmission, this may result in delays in the transmission of other data, including other raster image data over the network, or in the inability to transmit other data altogether during the transmission of the raster image data, due to inadequate total bandwidth capacity of a given network link.
Further still, in some networks even if the maximum possible bandwidth is allocated to the transmission of raster image data, the transmission of the raster image data may still be unduly slow, and also delay or prevent other transmissions over the network for a relatively lengthy period of time. For example, the transfer of image data for a job, using 100 Megabits/second 100 Base-T, can consume the entire network bandwidth for up to two minutes.
Another problem arises in the amount of memory needed to store the raster image data. In order to store jobs, for example at 1 Gigabyte per job, the network storage device(s) must have large capacity, high access speed, and easily expandable memory resources.
Therefore a need exists for an improved technique for networking multiple RIPs, one or more PDSs and one or more storage devices which are remote to either the RIPs, or the PDS(s), or both.